H2A Histone Family, Member B (H2AFB)

The deduced 115-amino acid H2AFB protein has a calculated molecular mass of about 13 kD. It shares highest sequence identity with other H2A histones within the alpha helices of the histone fold, and it contains highly basic N and C termini. H2AFB is unique among H2A histones in that the protein does not possess conserved residues that are posttranslationally modified in other H2A histones, and the cDNA contains a polyadenylation sequence and poly(A) tail. Northern blot analysis detected a 0.9-kb transcript expressed only in testis. In 46,XY fibroblasts, fluorescence-tagged H2AFB localized to the nucleus. In female cells, it was excluded from Barr bodies.Double-labeling experiments showed colocalization of H2AFB and acetylated histone H4 in interphase nuclei and on metaphase chromosomes.